8.3 Below-the-Hook Device Inspection

8.3 Below-the-Hook Device Inspection

Quick Answer: Inspect below-the-hook (BTH) lifting devices—lifting beams, spreaders, plate clamps, and similar gear—under ASME B30.20 concepts: structure, welds, connection points, mechanical function, and identification/tags. The user performs frequent inspection before use. Defective BTH gear is removed from service, not “used carefully for one more plate.”

A below-the-hook lifting device attaches to a hoist or crane hook to handle a load in a way slings alone cannot: spread lift points, grip plate edges, support long loads, or provide engineered attachment geometry. When a spreader beam cracks at a weld or a plate clamp’s jaws are worn smooth, the failure mode can be sudden and total. Level I riggers may not design BTH devices, but they must inspect them before use and refuse damaged equipment.

B30.20 Context for Level I

ASME B30.20 is the primary consensus standard associated with below-the-hook lifting devices. Companion structural design guidance (often discussed alongside BTH practice) informs manufacturers; your Level I job is inspection and correct use awareness, not calculating section modulus.

Common BTH categories on Level I jobsites:

This section focuses on beams/spreaders and plate clamps—the BTH types most often tested in rigger inspection scenarios—plus the frequent inspection duty that applies across devices.

Frequent Inspection by the User Before Use

BTH devices follow the same two-tier philosophy as slings and hardware:

Frequent inspection is not optional because a periodic sticker is current. A beam that passed last quarter can be forklift-struck overnight. A clamp’s lock can fail on the last job of yesterday. Before you put the crane hook in the bail, walk the device.

Pre-use BTH checklist mindset

1. Identify — Read capacity, serial/ID, and any critical limitations on the tag/nameplate.
2. Structure — Look for bends, cracks, dents, corrosion, and missing parts.
3. Welds and connections — Cracked welds, loose bolts, elongated holes, damaged pin connections.
4. Function — Moving parts operate (clamps lock/unlock; adjustable spreads set and secure if designed to).
5. Rigging interfaces — Bail/hook ring, pad eyes, shackles supplied with the device.
6. Decide — Use, or tag out and segregate.

If identification is missing or unreadable, you cannot confirm capacity or configuration limits—remove from service until properly identified under a competent process.

Lifting Beams and Spreader Beams

Roles (inspection implications)

• Lifting beam (often a single upper attachment with lower lugs spaced apart): can introduce bending into the beam under load—structure and welds matter enormously.
• Spreader beam (upper spread of slings or multiple upper points with compression strut): designed to put the bar primarily in compression with lower vertical legs—still must be free of bends, cracks, and bad welds.

You do not need to redesign the beam on the exam; you need to reject damaged structure.

Structural damage

Sight along the beam length. Compare to “as-built” straightness when possible. Forklift impacts and improper storage (beam used as a pry bar, left under a load, or struck during travel) are common damage sources.

Cracked welds

Welds joining lugs, end plates, and flanges are frequent crack sites under cyclic lifting loads. Inspection practice:

• Look at toe of welds, ends of fillet welds, and areas with paint cracks that follow a weld line
• Watch for rust bleeding from tight cracks
• Never “cover” a crack with paint or tape and return to service

Any crack in a primary structural weld or member → remove from service. Repairs are engineering/manufacturer-authorized work—not a field stick weld by an unqualified person during lunch.

Missing tags and rating plates

BTH devices must carry identification that supports safe selection: rated capacity, manufacturer identification, device weight (often critical for crane capacity calculations), and serial/ID for inspection records. Some devices also mark allowable load configurations or sling angles.

Device weight painted or tagged on the beam matters: the crane sees beam weight + load. Missing data creates both inspection and lift-planning failures.

Connection hardware on the beam

Inspect shackles, pins, and cotters supplied or used with the beam as part of the BTH system. A perfect beam with a cracked shackle on the lower lug is still out of service for that configuration.

Plate Clamps

Plate clamps grip steel plate for vertical or horizontal lifting depending on clamp design. Misused or worn clamps drop plates—often with fatal results for anyone in the fall zone.

Jaw wear

Jaws (serrated or designed gripping surfaces) must bite the plate. Inspection:

Follow manufacturer wear limits. When jaws no longer present a defined gripping surface, remove the clamp from service (or replace jaws only through authorized procedures).

Cam function

Many clamps use a cam or linkage that increases grip as load is applied. Functional inspection:

• Cam moves freely through its range without binding
• Cam face not cracked, spalled, or worn beyond limits
• Pivot pins present, retained, and not excessively worn
• Return springs (if any) function so the clamp sets as designed

A clamp that will not cam into engagement, or that feels “mushy” at the pivot, is not ready for a plate lift.

Locking devices

Locks and latches keep the clamp engaged during the lift and may secure the open/closed state during set and release. Inspection:

If the lock does not work, do not lift. A clamp that can open under vibration or slack-to-load transitions is a drop hazard.

Plate clamp identification and suitability cues

• Legible WLL and manufacturer ID
• Marked plate thickness range (minimum/maximum) when provided—using a clamp outside its thickness range is a use error that inspection should prevent
• Vertical vs horizontal clamp type matched to the task (wrong type is a selection failure found during pre-use review)

Other BTH Inspection Themes (Awareness)

Removal Criteria Quick Reference (BTH)

Integrating BTH Inspection into the Lift Sequence

1. Select the device for load weight, geometry, and manufacturer limits.
2. Frequent-inspect structure, function, and tags.
3. Inspect accompanying shackles/slings the same shift.
4. After any shock load, side impact, plate slip event, or known overload, re-inspect before reuse.
5. Store beams off the ground where they will not be run over; hang or stage clamps so jaws are protected from dirt and impact.

Unauthorized field welding on a cracked lifting beam is as unacceptable as field-welding alloy chain. Repairs require competent processes; many damaged devices are permanently retired.

Exam Focus

Expect scenarios such as: cracked weld on a spreader, missing capacity tag on a lifting beam, worn plate-clamp jaws, inoperative lock, or a rigger skipping pre-use inspection because “we used it yesterday.” Correct answers emphasize user frequent inspection before use, remove from service for structural/tag/function defects, and refusal to improvise repairs. Distractors keep using the device at reduced load or ignore missing tags because the beam “looks heavy enough.”